How to fill fresh water tank

[MrMark52]

Do this - make sure all your water fixtures are closed.

Hook up your water meter and hose to your coach.

Fill the FW tank until the meter quits running or water starts either coming out of the overflow tube, or dripping out of the bottom of the coach, or the water meter quits seeing flow -
1. If water starts exiting the overflow, then whatever the water flow meter reads is how how big your FW tank is. Turn off the water, you have your answer.
2. If water starts running out of the bottom of the coach where it isn’t supposed to, then turn off the water and start searching for the leak. Once any leaks are corrected, repeat the fill procedure where you’ll end up at either step 1 or 3 of these 3 steps.
3. If the water flow meter stops reading and no water is coming out of the coach - then turn off the water, and don’t disconnect anything. Make sure your freshwater pump is OFF. EGo to one of your fixtures and see if you momentarily have water pressure (the result of the FW tank being pressurized). And if this is the case, you need to look for a shut-off valve or something blocking the FW tank overflow - FW tanks should never have anything blocking the overflow port as FW tanks are not designed to be pressurized.

[MrMark52]

Originally Posted by Ray,IN

If I follow your line of thinking you also never travel with a full fuel tank to keep weight down???
FWIW my MH handles much better with full fuel and fresh water tanks than when they are nearly empty. Fuel mileage is the same either way. What makes the biggest difference is when towing a car.

Your comparing apples to oranges - you have to have fuel in your tank or your not going anywhere.

You don’t have to have FW to get any where.

And, fuel weight is the reason fuel tanks are mostly centered on the chassis, or there will be 2 fuel tanks in order to center the weight load.

Nothing wrong with traveling with full FW tanks - the point I was making is there is a cost associated with it.
And if your coach has one of those new super modified flux-capacitor thingys, then maybe carrying a full load of water doesn’t cost you fuel mileage. (I would like to know of the make and model of the flux-capacitor you have though).

It is possible that a full FW tank could make your coach handle better - but I would certainly be looking at all the chassis variables (shocks, jounce bumpers, air bags, springs, sway bars and bushings, track bars, and front end alignment) to make sure they are in good condition before resigning myself to having to carry more weight to make our coach handle better.

I mean after all - 8.33#’s/gallon equates to, to, to, uh, er, well - a whole lot of vino that we could carry in place of FW.

[wopachop]

You might be able to physically see your vent. My fill tube and the overflow tube are both visible under the sink. I check for leaks occasionally after a fill. I hold 200g and make sure to fully fill it before camping.

Since youre at 80 gallons just keep filling very very slowly. Eventually water should exit the fill tube and another leak will show up from your vent tube.

Many fresh water tanks expand as they fill. They will balloon and cause damage. Ive seen a trailer floor develop a large hump because the owner had the hose cranked full blast and the vent tube couldn't keep up.

[tcg]

Can you see your tank? Mine is easily accessible under the bed, I can see how much water is in it with very little effort.

I fill mine until water comes out the vent.

What promoted you to use a water meter to begin with? Have you always used a meter?

Surely an extra 23 gallons would have caused something to bulge or a tank strap to break.

[JHinman]

tcg -

I picked up the water meter because I was installing a SeeLevel system and wanted to see how it was working. The SeeLevel instructions direct an installer to add 1/4 tank of fluid and verify that the sensor is operating, and the water meter allowed me to fill to exactly 1/4 of capacity. I’ve never used a meter with a trailer before.

My tank is between the floor and the Coroplast. I could see the water level while I had part of the Coroplast down to install the SeeLevel sensor. It seemed to be full right at the expected 72 gallons. I cannot see the to[mod the tank, though. Now that the Coroplast is back up I cannot see the tank at all.

I’ve filled the tank several times, and probably overfilled it every time. I’d expect damage if it is really bulged that much, but don’t see anything.

[tcg]

Originally Posted by JHinman

tcg -

I picked up the water meter because I was installing a SeeLevel system and wanted to see how it was working. The SeeLevel instructions direct an installer to add 1/4 tank of fluid and verify that the sensor is operating, and the water meter allowed me to fill to exactly 1/4 of capacity. I’ve never used a meter with a trailer before.

My tank is between the floor and the Coroplast. I could see the water level while I had part of the Coroplast down to install the SeeLevel sensor. It seemed to be full right at the expected 72 gallons. I cannot see the to[mod the tank, though. Now that the Coroplast is back up I cannot see the tank at all.

I’ve filled the tank several times, and probably overfilled it every time. I’d expect damage if it is really bulged that much, but don’t see anything.

In my opinion, there is no way you could over fill a tank by 23 gallons without causing damage to the tank. If the tank could swell to accommodate an extra 23 gallons something would give.

Are you using a gravity feed? Meaning is the hose just stuck in a hole or is it screwed to a fitting?

If it is just gravity feed, even if your vent tube was pinched or plugged water would shoot out the fill hole.

If you really want to satisfy you're curiosity you may have to visually access your tank once more to see exactly what's going on. The only other explanation would be the tank is not original and it is bigger.

Curiosity might get the better of me so I might just physically look at the tank. Might be a job for a cheap endoscope that everyone should own for looking into places we normally can't see like our colons and between walls.

Please let us know if you figure it out.

[JHinman]

This is how I fill the tank. This spigot has a small-diameter plastic tube that inserts a small distance into the inlet tube. No way it can plug the inlet.

Someone suggested I make sure I’m testing my meter at full flow. I’ll try that again tomorrow. This meter cost me a whole $20, so if it is really off at higher flow rates I’ll be only mildly surprised.

[wopachop]

Your overflow vent is right there in the pic. Top right.
I think you are all good man. My best guess right now is your meter is off.
The way you are filling is perfect.

If you want to confirm the vent is not plugged up just keep the water on. It will come out the fill tube and also the little hole to the top right.

Dont worry about overfilling. People with trailers put a hose into the fill. Go inside their house. Come outside to a giant puddle on their driveway. Its actually a good way to test the hose clamps on your fill tubes. You should find no evidence of water inside the trailer.

[JHinman]

I checked calibration of my hose-end meter today, just for grins.

I filled a bucket to 5.0 gallons and weighed it (subtracting the tare) to see how much water I actually put in the bucket.

If I fill the bucket slowly the meter reads 3.6% low. In other words I put 5.18 gallons into my bucket when the meter said 5.0 gallons.

If I fill the bucket with a wide-open valve the meter reads 1.6% high. That means 4.92 gallons instead of the 5.0 gallons indicated.

That is surprisingly accurate for a $20 meter, and within the tolerances the manufacturer claims.

All it does is confirm that my measurements are reasonable, and that I still don’t know why my tank seems to hold 30% more than it should.

[tcg]

Originally Posted by JHinman

That is surprisingly accurate for a $20 meter, and within the tolerances the manufacturer claims.

All it does is confirm that my measurements are reasonable, and that I still don’t know why my tank seems to hold 30% more than it should.

Only two choices left, your tank is blowing up like a ballon or it's not the original tank.

I guess there is a third option... you're filling up your floor with water but that would have left a puddle somewhere.

My money is on your tank is not original.

[JHinman]

I bought the 5er new, so I’d be surprised that it is not the standard tank.

Blowing it up like a balloon is most likely - it would take only 2 to 3 inches of expansion to get another 23 gallons. I just don’t know how to make it expand without pressure.

[darnold9999]

I would be cautious about overfilling. In my previous Rexair the FW tank was a 100 gallon tank. Don't have the exact dimensions but it was a roughly square tank but not very high so quite a large square. If filled until full and overflowing out the vent the tank would balloon up by several inches and create a huge pressure on the floor above the tank, once it expanded beyond the space above. The ballooning also put pressure on the edges of the tank so much so that it cracked. When I bought it it was cracked (only showed up when full), and once I had welded the tank it cracked again at the weld when it was next overfilled. Reinforced the edge and rewelded then never over filled the tank and it lasted 6 more years with no issues.

Bottom line a ballooning tank can put enormous pressure on walls and floors surrounding the tank even with a vent. You can put water in way faster than it can escape through the vent. If the vent is blocked or closed at 50PSI you can do a lot of damage before the tank itself cracks. I always keep a very close eye on the fill level and try to stop just before it is completely full. Removing, repairing and replacing a FW tank is not a fun job!

[JHinman]

I have heard that motor homes fill the fresh tank with the city water connection. That would allow applying the city water line pressure to the tank.

Every trailer/5er that I’ve had fills with gravity feed through a pipe in the side of the trailer. There is no direct connection between the hose and the tank, so no way to pressurize the tank contents.

[wopachop]

Originally Posted by JHinman

There is no direct connection between the hose and the tank, so no way to pressurize the tank contents.

Its logical what you are saying. Your fill hose is a smaller diameter so its not plugging up the fill tube.

Problem is that the water falling down the tube ends up plugging it. That tiny vent cant keep up and the tank becomes pressurized. Put some soapy water over the vent tube to confirm its allowing air to escape.

You could watch the bubbles on the vent as you fill. If the bubbles are blowing like crazy it might mean you are filling too fast. Ive never tried a soap test on the vent tube before. It takes me hours to fill my trailer. Rough guess i turn the hose down to around 1.5 gal per minute. I use a fill adapter like the OP. I can see my fill tube under the sink. Its a nice straight tube. I think in my example air is able to escape both the vent tube and also the fill tube with a very slow water stream.